Britain's Queen Elizabeth II greets Canadian Prime Minister Justin Trudeau during an audience at the Palace of Holyroodhouse in Edinburgh on July 5, 2017. (ANDREW MILLIGAN/AFP/Getty Images)

On Wednesday, Canadian Prime Minister Justin Trudeau met with the Queen at the Palace of Holyroodhouse and reportedly cracked a joke that made her Majesty laugh out loud. Continuing his tour around Scotland in celebration of Canada’s 150th anniversary of becoming a single country, the prime minister met with the queen to “honor her importance to Canada’s history and to thank her for her continued dedication to Canada.”

In the midst of the meeting, Trudeau was filmed telling the queen, “I’ve been offered an honorary degree at the University of Edinburgh. It probably dismays a number of my former professors to see me a doctor now — even an honorary [one].” The self-deprecating joke, which refers to the recent doctor “honoris causa” qualification bestowed on him by the Scottish university’s School of Social and Political Science, reportedly broke the queen’s polite veneer and she couldn’t hold back her smile.

Having previously met in 2015 when he was first elected, the queen and the prime minister seem to share a fondness for quippy one-liners. During the Commonwealth Heads of Government Dinner in Malta of that year, Trudeau had toasted the queen and reminded the crowd that he was the 12th Canadian prime minister to serve during Queen Elizabeth’s reign. “Thank you, Mr. prime minister of Canada, for making me feel so old,” the Queen replied in her own toast — a comment that was later tweeted out by the Royal Family. Watch the full exchange below.